Manhole cover and frame



March 19, l1940. v ELKlNGTQN 2,194,221

MANHOLE COVER AND FRAME Filed llarch 9, 1937 2 Sheets-Sheet 1 @DS g3g@ Uf@ f w22 23 :I A I. Q@ D O @Q tdi? *iw #di D EUR?? 5530;' F. i ,/ZZQ

Jil L L da ME@ @DDEE 27 /2 sv Armi/vins Patented Mar. 19, 194() Pr-TENT MANHOLE COVER AND FRAME Vivian Elkington, Dover,l England Application Marche, 1937, serial No. 129,941

`In Greatritain March 127,1' 1936 4 This invention relates to `covers and frames for manholes'and the like in general of the kind in y :which the cover closely fits the frame.

The :invention has for its primary object to *"5 provide a construction of manhole cover and .frame with which rebound under iastemoving Wheel loads is definitely eliminated. Further objects are to provide `a construction which v'is eminently suited to multiple covers and trench @110- cover constructions and'toy obviate the necessity that all the cover lparts in such a ymultiple or trench l cover and frame construction should be fof identicalisize. Hitherto it` has-been necessary 'when castingthe cover partsroi a multiple .or

15 `trench cover and frame to castalargenumber of'covers, select the smallest to'iwhich jigs fare then made and "thennallygrind al1/the',y other larger. coversi tothe jigs.

The inventioncomprises a closely tting cover '20 and frame construction for manholes xrandfthe parallelogram, the angles of which are not vright angles.

Eachof the said pair'ofoppositefsidesofl the covervpreferably consists oftwofmeeting plane '235 surfaces, the lower of which has -a greater inclination to" the verticaly than the upper.

fIt will be appreciated that one sideof thev cover in this construction engages beneath'thei-corresponding side of the frame so'that `ii" 'thecover and frame be laid in a roadway in suchaposition that the side of the aforesaidfpair of opposite .sides which makesf'an acute angle with the top surface oi the cover vfaces they traffic, any ltendency of the opposite lside of the cover to lift is preventedby reasonoi the fact that it. makes an obtuse angle with the tcp surfaceI of [the cover and engagesbeneath the frame. l

In order that the invention .may vbe better 60 understood and readily carried into-effect vreference may be had to the accompanying drawings in which:

Figure 1 is aplan view oa rectangularmanholecover. and frame. in accordance with theini 56 vention,

, Figure 2 is a sectionvthrough the cover and frame onv the line12-"2 of Figure 1,k f

14Figure?, ,is a section through Athe cover and f fra-me onthe'line of Figure 1, v f f Figure 4 is asimilar view to' Figure `1 showing thevmethod of fitting the frame sections to the cover,

Figure'5 is adi'agrammatic plan view showingy `rthey-method'of liittingrthre frame sections to the Hrespeotive cover parts in atrench cover,

gether to'fform therectangular frame lshown: rin 20 l Figure l.. 'Thecover lll is cast with inclined sides I9' to 22, Figures 2.and'3, the sides Handi@ being inclined ina similarsense-so that a section throughthe cover on theline 2-'2 of'Figure'l `is roughly in the iorm'of' a parallelogram, their@ angles of which are `not right angles, asi-shown in' Figure 2. If desired the other'sides 2l andf22 may also be inclinedl in a similar sense, but. as f shown'in Figure kr3 they are inclined oppositely more in accordance with normal practice. sides may be plane or curved but yas shownv in the'example illustrated, cach side :consists oi two parts, an upper part a anda lower part b; the said lower part having a greater inclination tothe vertical' than the `upper part, so that each side; 35

' actually consistsof two meeting plane surfaces.

The frame sections 23 to 2li have inner walls conforming exactly to the sides B9 to 22 respectively'of the cover and thelatterseatsupon horizontally projecting lparts or flanges c of said y4,0'

inner Walls as shown in Figures 2 and '3. l With rthis; arrangement of the cover and frame sides the -cover fits the'frame tightly, its sides being supported along ci and b and its base by the horizontal part c. Due to the horizontal seatingv c45 the cover l0 cannot sink and at the same time thereis no bursting pressure actingon the'insidev of the frame because the resultant force ofa load applied to the cover Ill acts vertically downwards and there is no possibility of cover move- ,50

ment sideways within the frame due toy the contour of the partsl d and hand to the fact that the vcover is closely confined` within the, frame. v Furthermore the cover cannot rock when traic passes iover it/due to the fact that the side Eil ofy55f Falsa);

the cover engages beneath the frame section 24 which positively prevents any lift at this end. Nevertheless, the cover does not bind within the frame and may readily be removed, as will be more clearly explained hereafter, as due to the contour of the parts a b of the sides slight upward movement, amounting to a few hundredths of an inch only, of the side I9 of the cover frees the cover to permit easy withdrawal. The frame sections 23 to 26 are channeled as shown, the upper wall of the channel consisting merely of cross webs 2l and 27a, between the inner and outer walls of the frame sections due to the provision of apertures 23 in the said upper wall. These cross webs are partial as shown in Figs. 2 and 3, where they come between the main Webs of the cover as at 21 and complete, that is to say they extend over the complete cross section of the frame, where they correspond to or come opposite the main webs of the cover as at 21a. The side 2U of the cover Il) engages beneath the corresponding side 24 of the frame so that if the cover and frame be laid in a roadway in such a position that what may be termed the acute angled side i9 of the cover faces the traffic, any tendency of the side 2E) of the cover to lift is prevented by reason of the fact that it is obtuse angled and engages beneath the frame section 24. 'I'he frame sections are concrete lled being preferably pushed down into the concrete bed in order to compact the concrete filling in the frame channel to reinforce the latter and the cover may also be lled With concrete or Wood blocks.

Referring to Figure 4, the frame sections 23 to 25 are fitted to the cover l0 in the manner indicated, It will be noted that the sections 23 and 24 each consist of a straight side piece of the frame and corners, the horizontally projecting parts c being cut away adjacent the corner parts as shown. In assembling the frame the sections 25 and 26 are fitted up to the cover lil as shown and then the sections 23 and 24 are offered up against the end faces of the sections 25 and 253. If either of the sections 25 and 26 are slightly too long it is merely necessary to grind one of the end faces of the channel, which operation may be readily performed with a portable grinding machine. The sections 23 and 2li are then secured to the sections 25 and 26 by bolts passed through the elongated bolt holes 29 in cross webs near the ends of each of the sections 23 to 26. If either of the sections 23 and 24 are slightly too long or too short they may still be accurately fitted to the cover due to the fact that the holes 29 are elongated to permitv such accurate fitting. The frame sections are finally secured in their bolted positions by running hard lead or other keying metal into the chambers 3B, Figure l., formed between the various frame sections such nal securing also providing for accurate fitting of the frame sections to the cover in the case of either of the sections 25 or 26 being slightly too short. This method of fitting the frame sections to the cover is of particular' advantage in the case of multiple or trench covers. Fig s 5 and 6 show the method applied to a trench cov r in which the separate cover parts Ilia, lb, ic vary in size within a few thousandths of an inch, the variation being shown greatly exaggerated. In laying this trench cover and frame the frame sections 23, 25a and 25o. are fitted to the first cover part Ilia as described with reference to Figure 4, the fourth section being omitted as the second cover part lob seats directly on the cover part lila as shown in Figure 6.

The side frame sections 25h, 26h are then, together with their cover part |01), brought up to the ends of the frame sections 25a, 26a, and cover part Illa, respectively the frame sections 25a and 25h and 26a and 26h being adapted to their respective cover parts and at the same time to each other by virtue of the bolt and elongated bolt-hole connection already described with reference to Figure 4. The same procedure is adopted in fitting the frame sections 25e and 26C and subsequent sections, the frame sections al- Ways being ground olf to the exact length of their cover parts or made up to that length by the hard lead or other keying metal poured into the chambers 30. It will be noted that in effect the frame sections are built up around their respective cover parts and need not be precisely accurately in line with each other. The nal end frame section is of the same form as the section 24 shown in Figures 2 and 4.

In the drawings the covers appear to be precisely rectangular, but in fact, they are not. as it is essential, in order to facilitate easy removal, that one end of the cover is fractionally wider than the other. matically in Figure 7 where it will be observed the end R of the cover, which has to be raised slightly to break the joint when it is desired to move the cover, is fractionally wider than the other end L so that when once the cover has been freed from its frame it can be lifted and drawn off longitudinally over the end oi' the frame. The difference in width is of course only slight and in practice it has been found that in a cover 30 inches long a difference of only @1f of an inch suiices.

A suitable tool or accessory device may be employed for raising the end of the cover to break the joint between it and the frame.

I claim:

l. A cast metal cover and frame construction for manholes', comprising a rectangular frame having horizontally projecting parts forming a cover-seating surface and a rectangular cover seating upon said horizontally projecting parts and having at one end an integral part projecting downwardly and outwardly from the cover surface beneath a corresponding downwardly and inwardly recessed part of the frame whereby undesired rocking or lifting of the cover is prevented.

2. A cast metal cover and frame construction for manholes, comprising a frame having hori- Zontally projecting parts forming a cover-seating surface and a cover seating upon said horizontally projecting parts, one pair of opposite sides at least of said cover and frame being inclined in a similar sense so that a section through the cover perpendicular to said opposite sides is roughly in the form of a parallelcgram. the gles of which are not right angles.

3. A cast metal cover and frame construction for manholes, comprising a frame having horizontally projecting parts forming a cover-seat-V ing surface and a cover seating upon said hori Zontally projecting parts, one pair of opposite sides at least of said cover and frame being inclined in a similar sense and each side of said pair consisting of two meeting plane surfaces disposed at different inclinations. the lower of which has a greater inclination to thc vertical than the upper, so that a section through the cover perpendicular to said opposite sides is roughly in the form of a parallelogram, thel angles of which are not right angles.

This is illustrated diagram-y 4. A cast metal cover and frame construction for manholes, comprising a frame of substantially inverted U section having horizontally projecting parts constituting part of the inverted U and forming a cover-seating surface and a cover seating upon said horizontally projecting parte' and Vhaving a part projecting beneath a part of the frame whereby undesired rocking or lifting of the cover is prevented.

5. A cast metal cover and frame construction for manholes according to claim 1 and having the frame constructed in sections secured together adjacent the corners of the frame, comprising means to modify the alignment of the sections of the frame, one relative to the other, upon assembly, f

6. A cast metal vcover and frame construction for manholes according to claim 1 and having the frame constructed in sections, each of channel section with cross Webs near its ends having elongated bolt holes therein, and bolts passing through `said elongated bolt holes to secure the sections together While enabling them to loc iitted up to the cover. i

7. A cast metal cover and frame construction for manholes, comprising a frame having horizontally projecting parts forming a cover-seating surfacey and a cover seating upon said horizontally projecting parts, one end of said frame and cover being fractionally Wider than th other. Y

VIVIAN ELKINGTON. 

